The prior art teaches the practice of measuring the amplitudes of fields of forward scattered/reflected beams by an object as a function of angle of incidence in ellipsometric measurements. The prior art does not, however, teach backscattered imaging of an object by measuring amplitudes of fields of backscattered beams by an object using either interferometric non-ellipsometric or in interferometric ellipsometric measurements. Nor does it teach backscattered imaging involving joint measurements of conjugated quadratures of fields of backscattered beams by an object using either interferometric non-ellipsometric or in interferometric ellipsometric measurements.
The prior art also teaches the practice of measuring the amplitudes of fields of forward scattered/reflected beams by an object as a function of angle of incidence in ellipsometric measurements for a single spot on a substrate or for a small number of spots on a substrate. It does not, however, teach the practice of backscattered imaging or of measuring the amplitudes of fields of forward scattered/reflected beams by spots in or on a substrate by measuring simultaneously the amplitudes of fields of the backscattered beams or of the forward scattered/reflected beams by an array of a large number of spots in or on an object in either non-interferometric or in interferometric ellipsometric measurements. Nor does it teach the practice of backscattered imaging or of measuring the amplitudes of fields of forward scattered/reflected beams by spots in or on a substrate with simultaneous joint measurements of conjugated quadratures of fields of the backscattered beams or of the forward scattered/reflected beams by a large array of spots in or on an object in interferometric ellipsometric or non-ellipsometric measurements.